Isolating the introduction of software defects in a dispersed storage network

ABSTRACT

Methods and apparatus for isolating the introduction of software defects in a dispersed storage network (DSN) are disclosed. In various embodiments, a search strategy is employed whereby after identifying a test failure in a current version of the memory software code, a sequence of interim versions of the code between the current version of the memory software code and a previous successfully tested version of the code is determined. A first version of the memory software code is selected from the sequence of interim versions (e.g., from the middle of or approximately in the middle of the sequence) and tested. When testing of the first version does not result in a test failure, a second version of the memory software code is tested, the second version selected from a sub-sequence of the sequence of interim versions between the first version of the code and the current version of the code.

CROSS REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. § 120 as a continuation of U.S. Utility application Ser. No.15/248,772, entitled “ISOLATING THE INTRODUCTION OF SOFTWARE DEFECTS INA DISPERSED STORAGE NETWORK,” filed Aug. 26, 2016, which claims prioritypursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No.62/314,839, entitled “PROCESSING AN ENCODED DATA SLICE IN A DISPERSEDSTORAGE NETWORK,” filed Mar. 29, 2016, both of which are herebyincorporated herein by reference in their entirety and made part of thepresent U.S. Utility Patent Application for all purposes.

BACKGROUND Technical Field of the Invention

This invention relates generally to computer networks, and moreparticularly to isolating the introduction of software defects in adispersed storage network.

Description of Related Art

Computing devices are known to communicate data, process data, and/orstore data. Such computing devices range from wireless smart phones,laptops, tablets, personal computers (PC), work stations, and video gamedevices, to data centers that support millions of web searches, stocktrades, or on-line purchases every day. In general, a computing deviceincludes a central processing unit (CPU), a memory system, userinput/output interfaces, peripheral device interfaces, and aninterconnecting bus structure.

As is further known, a computer may effectively extend its CPU by using“cloud computing” to perform one or more computing functions (e.g., aservice, an application, an algorithm, an arithmetic logic function,etc.) on behalf of the computer. Further, for large services,applications, and/or functions, cloud computing may be performed bymultiple cloud computing resources in a distributed manner to improvethe response time for completion of the service, application, and/orfunction. For example, Hadoop is an open source software framework thatsupports distributed applications enabling application execution bythousands of computers.

In addition to cloud computing, a computer may use “cloud storage” aspart of its memory system. As is known, cloud storage enables a user,via its computer, to store files, applications, etc. on a remote storagesystem. The remote storage system may include a RAID (redundant array ofindependent disks) system and/or a dispersed storage system that uses anerror correction scheme to encode data for storage.

In a RAID system, a RAID controller adds parity data to the originaldata before storing it across an array of disks. The parity data iscalculated from the original data such that the failure of a single disktypically will not result in the loss of the original data. While RAIDsystems can address certain memory device failures, these systems maysuffer from effectiveness, efficiency and security issues. For instance,as more disks are added to the array, the probability of a disk failurerises, which may increase maintenance costs. When a disk fails, forexample, it needs to be manually replaced before another disk(s) failsand the data stored in the RAID system is lost. To reduce the risk ofdata loss, data on a RAID device is often copied to one or more otherRAID devices. While this may reduce the possibility of data loss, italso raises security issues since multiple copies of data may beavailable, thereby increasing the chances of unauthorized access. Inaddition, co-location of some RAID devices may result in a risk of acomplete data loss in the event of a natural disaster, fire, powersurge/outage, etc.

SUMMARY

According to an embodiment of the present invention, a method isprovided for isolating the introduction of software defects in adispersed storage network (DSN). In this embodiment, after identifying atest failure in a current version of the memory software code, asequence of interim versions of the memory software code between thecurrent version of the memory software code and a previous successfullytested version of the code is determined. A first version of the memorysoftware code is selected from the sequence of interim versions (e.g.,from the middle of or approximately in the middle of the sequence) andtested. When testing of the first version does not result in a testfailure, a second version of the memory software code is tested, thesecond version selected from a sub-sequence of the sequence of interimversions between the first version of the code and the current versionof the code. In a further embodiment, when testing of the first versionresults in a test failure, a third version of the memory software codeis tested, the third version selected from a sub-sequence of thesequence of interim versions between the first version of the code andthe previous successfully tested version of the code. In this manner,software testing failures can be rapidly traced to an underlying codechange.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of an embodiment of a dispersed, ordistributed, storage network (DSN) in accordance with the presentdisclosure;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the present disclosure;

FIG. 3 is a schematic block diagram of an example of dispersed storageerror encoding of data in accordance with the present disclosure;

FIG. 4 is a schematic block diagram of a generic example of an errorencoding function in accordance with the present disclosure;

FIG. 5 is a schematic block diagram of a specific example of an errorencoding function in accordance with the present disclosure;

FIG. 6 is a schematic block diagram of an example of slice naminginformation for an encoded data slice (EDS) in accordance with thepresent disclosure;

FIG. 7 is a schematic block diagram of an example of dispersed storageerror decoding of data in accordance with the present disclosure;

FIG. 8 is a schematic block diagram of a generic example of an errordecoding function in accordance with the present disclosure;

FIG. 9 is a schematic block diagram of an example of a dispersed storagenetwork in accordance with the present disclosure;

FIG. 10A is a schematic diagram of another embodiment of a dispersedstorage network in accordance with the present disclosure;

FIG. 10B is a schematic diagram of another embodiment of a dispersedstorage network in accordance with the present disclosure; and

FIG. 11 is a block diagram illustrating differing versions of memorysoftware code in accordance with the present invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic block diagram of an embodiment of a dispersed, ordistributed, storage network (DSN) 10 that includes a plurality ofcomputing devices 12-16, a managing unit 18, an integrity processingunit 20, and a DSN memory 22. The components of the DSN 10 are coupledto a network 24, which may include one or more wireless and/or wirelined communication systems; one or more non-public intranet systemsand/or public internet systems; and/or one or more local area networks(LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of storage units 36 that may belocated at geographically different sites (e.g., one in Chicago, one inMilwaukee, etc.), at a common site, or a combination thereof. Forexample, if the DSN memory 22 includes eight storage units 36, eachstorage unit is located at a different site. As another example, if theDSN memory 22 includes eight storage units 36, all eight storage unitsare located at the same site. As yet another example, if the DSN memory22 includes eight storage units 36, a first pair of storage units are ata first common site, a second pair of storage units are at a secondcommon site, a third pair of storage units are at a third common site,and a fourth pair of storage units are at a fourth common site. Notethat a DSN memory 22 may include more or less than eight storage units36.

Each of the computing devices 12-16, the managing unit 18, and theintegrity processing unit 20 include a computing core 26, and networkinterfaces 30-33 which can be part of or external to computing core 26.Computing devices 12-16 may each be a portable computing device and/or afixed computing device. A portable computing device may be a socialnetworking device, a gaming device, a cell phone, a smart phone, adigital assistant, a digital music player, a digital video player, alaptop computer, a handheld computer, a tablet, a video game controller,and/or any other portable device that includes a computing core. A fixedcomputing device may be a computer (PC), a computer server, a cableset-top box, a satellite receiver, a television set, a printer, a faxmachine, home entertainment equipment, a video game console, and/or anytype of home or office computing equipment. Note that each of themanaging unit 18 and the integrity processing unit 20 may be separatecomputing devices, may be a common computing device, and/or may beintegrated into one or more of the computing devices 12-16 and/or intoone or more of the storage units 36.

Each interface 30, 32, and 33 includes software and hardware to supportone or more communication links via the network 24 indirectly and/ordirectly. For example, interface 30 supports a communication link (e.g.,wired, wireless, direct, via a LAN, via the network 24, etc.) betweencomputing devices 14 and 16. As another example, interface 32 supportscommunication links (e.g., a wired connection, a wireless connection, aLAN connection, and/or any other type of connection to/from the network24) between computing devices 12 and 16 and the DSN memory 22. As yetanother example, interface 33 supports a communication link for each ofthe managing unit 18 and the integrity processing unit 20 to the network24.

Computing devices 12 and 16 include a dispersed storage (DS) clientmodule 34, which enables the computing device to dispersed storage errorencode and decode data (e.g., data object 40) as subsequently describedwith reference to one or more of FIGS. 3-8. In this example embodiment,computing device 16 functions as a dispersed storage processing agentfor computing device 14. In this role, computing device 16 dispersedstorage error encodes and decodes data on behalf of computing device 14.With the use of dispersed storage error encoding and decoding, the DSN10 is tolerant of a significant number of storage unit failures (thenumber of failures is based on parameters of the dispersed storage errorencoding function) without loss of data and without the need for aredundant or backup copies of the data. Further, the DSN 10 stores datafor an indefinite period of time without data loss and in a securemanner (e.g., the system is very resistant to unauthorized attempts ataccessing the data).

In operation, the managing unit 18 performs DS management services. Forexample, the managing unit 18 establishes distributed data storageparameters (e.g., vault creation, distributed storage parameters,security parameters, billing information, user profile information,etc.) for computing devices 12-16 individually or as part of a group ofuser devices. As a specific example, the managing unit 18 coordinatescreation of a vault (e.g., a virtual memory block associated with aportion of an overall namespace of the DSN) within the DSN memory 22 fora user device, a group of devices, or for public access and establishesper vault dispersed storage (DS) error encoding parameters for a vault.The managing unit 18 facilitates storage of DS error encoding parametersfor each vault by updating registry information of the DSN 10, where theregistry information may be stored in the DSN memory 22, a computingdevice 12-16, the managing unit 18, and/or the integrity processing unit20. The DS error encoding parameters (e.g., or dispersed storage errorcoding parameters) include data segmenting information (e.g., how manysegments data (e.g., a file, a group of files, a data block, etc.) isdivided into), segment security information (e.g., per segmentencryption, compression, integrity checksum, etc.), error codinginformation (e.g., pillar width, decode threshold, read threshold, writethreshold, etc.), slicing information (e.g., the number of encoded dataslices that will be created for each data segment); and slice securityinformation (e.g., per encoded data slice encryption, compression,integrity checksum, etc.).

The managing unit 18 creates and stores user profile information (e.g.,an access control list (ACL)) in local memory and/or within memory ofthe DSN memory 22. The user profile information includes authenticationinformation, permissions, and/or the security parameters. The securityparameters may include encryption/decryption scheme, one or moreencryption keys, key generation scheme, and/or data encoding/decodingscheme.

The managing unit 18 creates billing information for a particular user,a user group, a vault access, public vault access, etc. For instance,the managing unit 18 tracks the number of times a user accesses anon-public vault and/or public vaults, which can be used to generateper-access billing information. In another instance, the managing unit18 tracks the amount of data stored and/or retrieved by a user deviceand/or a user group, which can be used to generate per-data-amountbilling information.

As another example, the managing unit 18 performs network operations,network administration, and/or network maintenance. Network operationsincludes authenticating user data allocation requests (e.g., read and/orwrite requests), managing creation of vaults, establishingauthentication credentials for user devices, adding/deleting components(e.g., user devices, storage units, and/or computing devices with a DSclient module 34) to/from the DSN 10, and/or establishing authenticationcredentials for the storage units 36. Network administration includesmonitoring devices and/or units for failures, maintaining vaultinformation, determining device and/or unit activation status,determining device and/or unit loading, and/or determining any othersystem level operation that affects the performance level of the DSN 10.Network maintenance includes facilitating replacing, upgrading,repairing, and/or expanding a device and/or unit of the DSN 10.

To support data storage integrity verification within the DSN 10, theintegrity processing unit 20 (and/or other devices in the DSN 10) mayperform rebuilding of ‘bad’ or missing encoded data slices. At a highlevel, the integrity processing unit 20 performs rebuilding byperiodically attempting to retrieve/list encoded data slices, and/orslice names of the encoded data slices, from the DSN memory 22.Retrieved encoded slices are checked for errors due to data corruption,outdated versioning, etc. If a slice includes an error, it is flagged asa ‘bad’ or ‘corrupt’ slice. Encoded data slices that are not receivedand/or not listed may be flagged as missing slices. Bad and/or missingslices may be subsequently rebuilt using other retrieved encoded dataslices that are deemed to be good slices in order to produce rebuiltslices. A multi-stage decoding process may be employed in certaincircumstances to recover data even when the number of valid encoded dataslices of a set of encoded data slices is less than a relevant decodethreshold number. The rebuilt slices may then be written to DSN memory22. Note that the integrity processing unit 20 may be a separate unit asshown, included in DSN memory 22, included in the computing device 16,and/or distributed among the storage units 36.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (IO)controller 56, a peripheral component interconnect (PCI) interface 58,an IO interface module 60, at least one IO device interface module 62, aread only memory (ROM) basic input output system (BIOS) 64, and one ormore memory interface modules. The one or more memory interfacemodule(s) includes one or more of a universal serial bus (USB) interfacemodule 66, a host bus adapter (HBA) interface module 68, a networkinterface module 70, a flash interface module 72, a hard drive interfacemodule 74, and a DSN interface module 76.

The DSN interface module 76 functions to mimic a conventional operatingsystem (OS) file system interface (e.g., network file system (NFS),flash file system (FFS), disk file system (DFS), file transfer protocol(FTP), web-based distributed authoring and versioning (WebDAV), etc.)and/or a block memory interface (e.g., small computer system interface(SCSI), internet small computer system interface (iSCSI), etc.). The DSNinterface module 76 and/or the network interface module 70 may functionas one or more of the interface 30-33 of FIG. 1. Note that the IO deviceinterface module 62 and/or the memory interface modules 66-76 may becollectively or individually referred to as IO ports.

FIG. 3 is a schematic block diagram of an example of dispersed storageerror encoding of data. When a computing device 12 or 16 has data tostore it disperse storage error encodes the data in accordance with adispersed storage error encoding process based on dispersed storageerror encoding parameters. The dispersed storage error encodingparameters include an encoding function (e.g., information dispersalalgorithm, Reed-Solomon, Cauchy Reed-Solomon, systematic encoding,non-systematic encoding, on-line codes, etc.), a data segmentingprotocol (e.g., data segment size, fixed, variable, etc.), and per datasegment encoding values. The per data segment encoding values include atotal, or pillar width, number (T) of encoded data slices per encodingof a data segment (i.e., in a set of encoded data slices); a decodethreshold number (D) of encoded data slices of a set of encoded dataslices that are needed to recover the data segment; a read thresholdnumber (R) of encoded data slices to indicate a number of encoded dataslices per set to be read from storage for decoding of the data segment;and/or a write threshold number (W) to indicate a number of encoded dataslices per set that must be accurately stored before the encoded datasegment is deemed to have been properly stored. The dispersed storageerror encoding parameters may further include slicing information (e.g.,the number of encoded data slices that will be created for each datasegment) and/or slice security information (e.g., per encoded data sliceencryption, compression, integrity checksum, etc.).

In the present example, Cauchy Reed-Solomon has been selected as theencoding function (a generic example is shown in FIG. 4 and a specificexample is shown in FIG. 5); the data segmenting protocol is to dividethe data object into fixed sized data segments; and the per data segmentencoding values include: a pillar width of 5, a decode threshold of 3, aread threshold of 4, and a write threshold of 4. In accordance with thedata segmenting protocol, the computing device 12 or 16 divides the data(e.g., a file (e.g., text, video, audio, etc.), a data object, or otherdata arrangement) into a plurality of fixed sized data segments (e.g., 1through Y of a fixed size in range of Kilo-bytes to Tera-bytes or more).The number of data segments created is dependent of the size of the dataand the data segmenting protocol.

The computing device 12 or 16 then disperse storage error encodes a datasegment using the selected encoding function (e.g., Cauchy Reed-Solomon)to produce a set of encoded data slices. FIG. 4 illustrates a genericCauchy Reed-Solomon encoding function, which includes an encoding matrix(EM), a data matrix (DM), and a coded matrix (CM). The size of theencoding matrix (EM) is dependent on the pillar width number (T) and thedecode threshold number (D) of selected per data segment encodingvalues. To produce the data matrix (DM), the data segment is dividedinto a plurality of data blocks and the data blocks are arranged into Dnumber of rows with Z data blocks per row. Note that Z is a function ofthe number of data blocks created from the data segment and the decodethreshold number (D). The coded matrix is produced by matrix multiplyingthe data matrix by the encoding matrix.

FIG. 5 illustrates a specific example of Cauchy Reed-Solomon encodingwith a pillar number (T) of five and decode threshold number of three.In this example, a first data segment is divided into twelve data blocks(D1-D12). The coded matrix includes five rows of coded data blocks,where the first row of X11-X14 corresponds to a first encoded data slice(EDS 1_1), the second row of X21-X24 corresponds to a second encodeddata slice (EDS 2_1), the third row of X31-X34 corresponds to a thirdencoded data slice (EDS 3_1), the fourth row of X41-X44 corresponds to afourth encoded data slice (EDS 4_1), and the fifth row of X51-X54corresponds to a fifth encoded data slice (EDS 5_1). Note that thesecond number of the EDS designation corresponds to the data segmentnumber. In the illustrated example, the value X11=aD1+bD5+cD9,X12=aD2+bD6+cD10, . . . X53=mD3+nD7+oD11, and X54=mD4+nD8+oD12.

Returning to the discussion of FIG. 3, the computing device also createsa slice name (SN) for each encoded data slice (EDS) in the set ofencoded data slices. A typical format for a slice name 80 is shown inFIG. 6. As shown, the slice name (SN) 80 includes a pillar number of theencoded data slice (e.g., one of 1−T), a data segment number (e.g., oneof 1−Y), a vault identifier (ID), a data object identifier (ID), and mayfurther include revision level information of the encoded data slices.The slice name functions as at least part of a DSN address for theencoded data slice for storage and retrieval from the DSN memory 22.

As a result of encoding, the computing device 12 or 16 produces aplurality of sets of encoded data slices, which are provided with theirrespective slice names to the storage units for storage. As shown, thefirst set of encoded data slices includes EDS 1_1 through EDS 5_1 andthe first set of slice names includes SN 1_1 through SN 5_1 and the lastset of encoded data slices includes EDS 1_Y through EDS 5_Y and the lastset of slice names includes SN 1_Y through SN 5_Y.

FIG. 7 is a schematic block diagram of an example of dispersed storageerror decoding of a data object that was dispersed storage error encodedand stored in the example of FIG. 4. In this example, the computingdevice 12 or 16 retrieves from the storage units at least the decodethreshold number of encoded data slices per data segment. As a specificexample, the computing device retrieves a read threshold number ofencoded data slices.

In order to recover a data segment from a decode threshold number ofencoded data slices, the computing device uses a decoding function asshown in FIG. 8. As shown, the decoding function is essentially aninverse of the encoding function of FIG. 4. The coded matrix includes adecode threshold number of rows (e.g., three in this example) and thedecoding matrix in an inversion of the encoding matrix that includes thecorresponding rows of the coded matrix. For example, if the coded matrixincludes rows 1, 2, and 4, the encoding matrix is reduced to rows 1, 2,and 4, and then inverted to produce the decoding matrix.

FIG. 9 is a diagram of an example of a dispersed storage network. Thedispersed storage network includes a DS (dispersed storage) clientmodule 34 (which may be in computing devices 12, 14 and/or 16 of FIG.1), a network 24, and a plurality of DS units 1-n that includes two ormore DS units 36 of FIG. 1 (which form at least a portion of DS memory22 of FIG. 1), a DSN managing unit (not shown—device 18 in FIG. 1), anda DS integrity verification module (not shown—device 20 in FIG. 1). TheDS client module 34 includes an outbound DS processing section 81 and aninbound DS processing section 82. Each of the DS units 1-n includes acontroller 86, a processing module 84, memory 88, a DT (distributedtask) execution module 90, and a DS client module 34.

In an example of operation, the DS client module 34 receives data 92.The data 92 may be of any size and of any content, where, due to thesize (e.g., greater than a few Terabytes), the content (e.g., securedata, etc.), and/or concerns over security and loss of data, distributedstorage of the data is desired. For example, the data 92 may be one ormore digital books, a copy of a company's emails, a large-scale Internetsearch, a video security file, one or more entertainment video files(e.g., television programs, movies, etc.), data files, and/or any otherlarge amount of data (e.g., greater than a few Terabytes). Within the DSclient module 34, the outbound DS processing section 81 receives thedata 92. The outbound DS processing section 81 processes the data 92 toproduce slice groupings 96. As an example of such processing, theoutbound DS processing section 81 partitions the data 92 into aplurality of data partitions. For each data partition, the outbound DSprocessing section 81 dispersed storage (DS) error encodes the datapartition to produce encoded data slices and groups the encoded dataslices into a slice grouping 96.

The outbound DS processing section 81 then sends, via the network 24,the slice groupings 96 to the DS units 1-n of the DSN memory 22 ofFIG. 1. For example, the outbound DS processing section 81 sends slicegroup #1 to DS storage unit 1. As another example, the outbound DSprocessing section 81 sends slice group #n to DS unit #n.

In one example of operation, the DS client module 34 requests retrievalof stored data within the memory of the DS units 36. In this example,the task 94 is retrieve data stored in the DSN memory 22. Accordingly,and according to one embodiment, the outbound DS processing section 81converts the task 94 into a plurality of partial tasks 97 and sends thepartial tasks 97 to the respective DS storage units 1-n.

In response to the partial task 97 of retrieving stored data, a DSstorage unit 36 identifies the corresponding encoded data slices andretrieves them. For example, DS unit #1 receives partial task #1 andretrieves, in response thereto, retrieved slices #1. The DS units 36send their respective retrieved slices 98 to the inbound DST processingsection 82 via the network 24.

The inbound DS processing section 82 converts the retrieved slices 98into data 92. For example, the inbound DS processing section 82de-groups the retrieved slices 98 to produce encoded slices per datapartition. The inbound DS processing section 82 then DS error decodesthe encoded slices per data partition to produce data partitions. Theinbound DS processing section 82 de-partitions the data partitions torecapture the data 92. The inbound DS processing section can alsoindicate a result 99 of DS error decoding operations.

The DSN managing unit 18 of FIG. 1 may be used to facilitate isolatingthe introduction of software defects in the storage units or DS units(36) of FIGS. 1 and 9. Further explanations of this process are set outbelow in conjunction with FIGS. 10A and 10B.

FIG. 10A is a schematic block diagram of another embodiment of adispersed storage network that includes the computing device 16 of FIG.1, the dispersed storage network (DSN) managing unit 18 of FIG. 1, and aset of storage units 1-n (36-1, 36-2 . . . 36-n). Each storage unit maybe implemented utilizing the DS unit 36 of FIGS. 1 and 9. Hereafter, theset of storage units may be interchangeably referred to as a set of DSunits. The DSN functions to identify a software version associated witha software-based operational error.

FIG. 11 is a block diagram 1100 illustrating differing versions ofmemory software code in accordance with the present invention. In anexample of operation of the identifying of the software version, the DSNmanaging unit 18 detects the software operational error within the DSunits, where a software test performed on a version of software producesan unfavorable result. The detecting includes one or more ofinterpreting an error message, selecting the software test from aplurality of software tests, facilitating the exercising of the DS unitsoftware in accordance with the selected software test to produce asoftware test resultant, and indicating the software operational errorwhen the software test resultant compares unfavorably to an expectedsoftware test resultant. For example, the DSN managing unit 18 issues atest request(s) (m) to computing device 16 and the set of storage units(36-1, 36-2, . . . , 36-n), receives test responses (m) from units ofthe DSN, and interprets the test responses (m), where the computingdevice 16 may issue, via the network 24, test slices 1-n to the set ofstorage units (36-1, 36-2, . . . , 36-n) and interpret received testslices 1-n to produce at least some of the test responses.

Having detected the software operational error, the DSN managing unit 18identifies a previous version of software associated with favorablesoftware operation, where the software test performed on the previousversion of software produces a favorable result. In an example,identifying the previous version of software associated with favorablesoftware operation includes interpreting a software test record using anidentifier of the software test to identify the previous version. Havingidentified the previous version, the DSN managing unit 18 identifies asequence of software versions that includes a sequential series of oneor more interim software versions that ranges from the previous versionsoftware to the version of software (as shown as element 1110 in FIG.11). In an embodiment, identifying the sequence of software versionsincludes one or more of performing a lookup, interpreting a queryresult, interpreting an error message, and interpreting test records.

Having identified a sequence of software versions, the DSN managing unit18 identifies a defect root cause interim software version of the one ormore interim software versions utilizing a binary search software testapproach. As shown in FIG. 11, and will be explained in more detailbelow, the identifying includes, for a remaining sub-sequence of interimsoftware versions, selecting a middle software version as a next testinterim software version, selecting a software test associated with thesoftware operational error and the next test interim software version,loading corresponding units (e.g. computing device 16 and/or DS units36) of the DSN with the next interim software version, performing theselected software test on the DS unit software in question to produce anext test interim software version test result, indicating to move to anolder interim software version when the test result is unfavorable orindicating to move to a newer interim software version when the testresult is favorable, repeating the binary search approach until locatingthe interim software version most associated with the softwareoperational error, and identifying the software version most associatedwith the software operational error as the defect root cause interimsoftware version. Having identified the defect root cause interimsoftware version, the DSN managing unit 18 outputs a test result thatincludes identification of the defect root cause interim softwareversion. While the middle in FIG. 11 is shown as the exact middlesoftware version, other embodiments could use an approximate middle byrounding up or down as needed if a true middle does not exist. Thisapproach will also work if something close to or near the middle ischosen, but the convergence rate will go down the further one gets fromutilizing the middle.

FIG. 10B is a flowchart illustrating an example of identifying asoftware version associated with a software-based operational error. Themethod includes a step 100 where a processing module (e.g., of adistributed storage and task network (DSN) managing unit) detects asoftware-based operational error within a dispersed storage unit where asoftware test performed on a version of DS unit software produces anunfavorable result. The detecting includes one or more of interpretingan error message, selecting the software test from a plurality ofsoftware tests, facilitating exercising the DS unit software inaccordance with the selected software test to produce a software testresultant, and indicating the software operational error when thesoftware test resultant compares unfavorably to an expected softwaretest resultant.

The method continues at the step 102 where the processing moduleidentifies a previous version of DS unit software associated withfavorable DS unit operation, where the software test performed on theprevious version of DS unit software produces a favorable result (1110in FIG. 11). For example, the processing module interprets a softwaretest record using an identifier of the software test to identify theprevious version of DS unit software associated with the favorableresult.

The method continues at the step 104 where the processing moduleidentifies a sequential series of one or more interim DS unit softwareversions that ranges from the previous version of DS unit software tothe current version of DS unit software (1112 in FIG. 11). Theidentifying includes one or more of performing a lookup, interpreting aquery result, interpreting an error message, and interpreting testrecords.

The method continues at the step 106 where the processing moduleidentifies a defect root cause interim DS unit software versionassociated with the software-based operational error utilizing a binarysearch test software approach. The identifying includes, for a remainingsub-sequence of interim software versions, selecting a middle softwareversion as a next test interim software version (1114 in FIG. 11),selecting a software test associated with the software operational errorand the next test interim software version, loading corresponding units(e.g. computing device 16 and/or DS units 36) and modules of the DSNwith the next test interim software version, performing the selectedsoftware test on the DS unit software to produce a next test interimsoftware version test result, indicating to move to an older interimsoftware version (e.g., in the middle of a new remaining sub-sequence)when the test result is unfavorable or indicate to move to a newerinterim software version when the test result is favorable, repeatingthe binary search approach until locating the interim software versionmost associated with the software operational error, and identifying thesoftware version most associated with the software operational error asthe defect root cause interim software version. The second and thirdinterim versions, depending on the outcome of the first and secondinterim version tests, are illustrated in FIG. 11 as 1116 and 1118respectively. The subsequent interim versions to test can be determinedin a similar manner.

According to another embodiment, in certain high-priority times, when itis critical to isolate the test as rapidly as possible, or to completean automated test as rapidly as possible, elastic-resources may beprocured to instantiate multiple DS unit software instances on multipleDSN units and modules (e.g. computing device 16 and/or DS units 36) uponwhich different sub-sets of the full suite of automated tests can beindependently executed. For example, if the test suite includes 200tests, and 4 DS units are made available for a high-priority rushed testexecution, then 50 of the 200 tests may be assigned to be executedagainst each of the 4 DS units. In this manner, each test failure can berapidly traced to the underlying code change, and similarly, when fixed,this same system can rapidly determine the code change introduction thatresulted in the fix (as determined by a test that was failing but is nowpassing).

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, text, graphics, audio, etc. any of which may generally bereferred to as ‘data’).

The methods described above in conjunction with the computing device andthe storage units can alternatively be performed by other modules of thedispersed storage network or by other devices. For example, anycombination of a first module, a second module, a third module, a fourthmodule, etc. of the computing device and the storage units may performthe method described above. In addition, at least one memory section(e.g., a first memory section, a second memory section, a third memorysection, a fourth memory section, a fifth memory section, a sixth memorysection, etc. of a non-transitory computer readable storage medium) thatstores operational instructions can, when executed by one or moreprocessing modules of one or more computing devices and/or by thestorage units of the dispersed storage network (DSN), cause the one ormore computing devices and/or the storage units to perform any or all ofthe method steps described above.

As may be used herein, the terms “substantially” and “approximately”provide an industry-accepted tolerance for its corresponding term and/orrelativity between items. For some industries, an industry-acceptedtolerance is less than one percent and, for other industries, theindustry-accepted tolerance is 10 percent or more. Other examples ofindustry-accepted tolerance range from less than one percent to fiftypercent. Industry-accepted tolerances correspond to, but are not limitedto, component values, integrated circuit process variations, temperaturevariations, rise and fall times, thermal noise, dimensions, signalingerrors, dropped packets, temperatures, pressures, material compositions,and/or performance metrics. Within an industry, tolerance variances ofaccepted tolerances may be more or less than a percentage level (e.g.,dimension tolerance of less than +/−1%). Some relativity between itemsmay range from a difference of less than a percentage level to a fewpercent. Other relativity between items may range from a difference of afew percent to magnitude of differences.

As may also be used herein, the term(s) “configured to”, “operablycoupled to”, “coupled to”, and/or “coupling” includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for an example of indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.

As may even further be used herein, the term “configured to”, “operableto”, “coupled to”, or “operably coupled to” indicates that an itemincludes one or more of power connections, input(s), output(s), etc., toperform, when activated, one or more its corresponding functions and mayfurther include inferred coupling to one or more other items. As maystill further be used herein, the term “associated with”, includesdirect and/or indirect coupling of separate items and/or one item beingembedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may be used herein, one or more claims may include, in a specificform of this generic form, the phrase “at least one of a, b, and c” orof this generic form “at least one of a, b, or c”, with more or lesselements than “a”, “b”, and “c”. In either phrasing, the phrases are tobe interpreted identically. In particular, “at least one of a, b, and c”is equivalent to “at least one of a, b, or c” and shall mean a, b,and/or c. As an example, it means: “a” only, “b” only, “c” only, “a” and“b”, “a” and “c”, “b” and “c”, and/or “a”, “b”, and “c”.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, and/or “processing unit” may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may be, or furtherinclude, memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of another processing module, module, processing circuit,and/or processing unit. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from Figureto Figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

As may further be used herein, a computer readable memory includes oneor more memory elements. A memory element may be a separate memorydevice, multiple memory devices, or a set of memory locations within amemory device. Such a memory device may be a read-only memory, randomaccess memory, volatile memory, non-volatile memory, static memory,dynamic memory, flash memory, cache memory, and/or any device thatstores digital information. The memory device may be in a form a solidstate memory, a hard drive memory, cloud memory, thumb drive, servermemory, computing device memory, and/or other physical medium forstoring digital information. A computer readable memory/storage medium,as used herein, is not to be construed as being transitory signals perse, such as radio waves or other freely propagating electromagneticwaves, electromagnetic waves propagating through a waveguide or othertransmission media (e.g., light pulses passing through a fiber-opticcable), or electrical signals transmitted through a wire.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method for execution by one or more processingmodules of one or more computing devices of a dispersed storage network(DSN) to identify a defect root cause interim software version, themethod comprises: receiving an indication of a software operationalerror resulting from testing performed on a current version of a memorysoftware code; in response to receiving the indication of a softwareoperational error, identifying a sequence of interim versions of thememory software code between the current version of the memory softwarecode and a previous version of the memory software code associated withfavorable software operation; identifying a first version of the memorysoftware code from the sequence of interim versions of the memorysoftware code; facilitating a first test of the first version of thememory software code by at least one device of the DSN; determining ifthe first test results in a test failure; in response to determiningthat the first test does not result in a test failure: identifying asecond version of the memory software code from the sequence of interimversions of the memory software code, where the second version of thememory software code is in a sub-sequence of the sequence of interimversions of the memory software code between the first version of thememory software code and the current version of the memory softwarecode; and facilitating a second test, by the at least one device, of thesecond version of the memory software code; and in response todetermining that the first test results in a test failure: identifying athird version of the memory software code from the sequence of interimversions of the memory software code, where the third version of thememory software code is in a sub-sequence of the sequence of interimversions of the memory software code between the first version of thememory software code and the previous version of the memory softwarecode associated with favorable software operation; and facilitating athird test, by the at least one device, of the third version of thememory software code.
 2. The method of claim 1, wherein facilitating thefirst test includes: facilitating loading of the first version of thememory software code on the at least one device of the DSN.
 3. Themethod of claim 2, wherein facilitating loading of the first version ofthe memory software code on the at least one device of the DSN includes:facilitating loading of the first version of the memory software code ona first device and a second device of the DSN, wherein a portion of thefirst test is performed on the first device and a differing portion ofthe first test is performed on the second device.
 4. The method of claim1, wherein the first version of the memory software code is in a middleof or approximately in the middle of the sequence of interim versions ofthe memory software code.
 5. The method of claim 4, wherein the secondversion of the memory software code is in a middle of or approximatelyin the middle of the sub-sequence of the sequence of interim versions ofthe memory software code.
 6. The method of claim 1, further comprising:iteratively facilitating additional testing of additional versions ofthe memory software code identified in additional sub-sequences of thesequence of interim versions to identify the defect root cause interimsoftware version.
 7. The method of claim 1, wherein receiving theindication of the software operational error resulting from testingperformed on the current version of the memory software code includesone or more selected from the group consisting of: interpreting an errormessage, selecting a test from a plurality of software tests,facilitating exercise of the memory software code in accordance with aselected test, and indicating a software error when a software testresultant compares unfavorably to an expected software test resultant.8. The method of claim 1, wherein receiving the indication of thesoftware operational error resulting from testing performed on thecurrent version of the memory software code includes one or moreselected from the group consisting of: issuing a test request to astorage unit of the DSN, and receiving a test response from a storageunit of the DSN.
 9. The method of claim 1, wherein receiving theindication of the software operational error resulting from testingperformed on the current version of the memory software code includesissuing a test request to a device of the DSN that is configured tosubsequently issue first test slices to a storage unit of the DSN andinterpret second test slices received from the storage unit.
 10. Themethod of claim 1, wherein identifying the sequence of interim versionsof the memory software code includes interpreting a software test recordusing an identifier of a software test performed on the previous versionof the memory software code associated with favorable softwareoperation.
 11. A computing device for use in a dispersed storage network(DSN), the computing device comprises: an interface; a local memorycomprising instructions; and a processing module operably coupled to theinterface and the local memory, wherein the processing module executesthe instructions to: receive, via the interface, an indication of asoftware operational error resulting from testing performed on a currentversion of a memory software code; in response to receiving theindication of a software operational error, identify a sequence ofinterim versions of the memory software code between the current versionof the memory software code and a previous version of the memorysoftware code associated with favorable software operation; identify afirst version of the memory software code from the sequence of interimversions of the memory software code; facilitate a first test of thefirst version of the memory software code by at least one device of theDSN; determine if the first test results in a test failure; in responseto determining that the first test does not result in a test failure:identify a second version of the memory software code from the sequenceof interim versions of the memory software code, where the secondversion of the memory software code is in a sub-sequence of the sequenceof interim versions of the memory software code between the firstversion of the memory software code and the current version of thememory software code; and facilitate a second test, by the at least onedevice, of the second version of the memory software code; and inresponse to determining that the first test results in a test failure:identify a third version of the memory software code from the sequenceof interim versions of the memory software code, where the third versionof the memory software code is in a sub-sequence of the sequence ofinterim versions of the memory software code between the first versionof the memory software code and the previous version of the memorysoftware code associated with favorable software operation; andfacilitate a third test, by the at least one device, of the thirdversion of the memory software code.
 12. The computing device of claim11, wherein facilitating the first test includes: facilitating, via theinterface, loading of the first version of the memory software code onthe at least one device of the DSN.
 13. The computing device of claim12, wherein facilitating loading of the first version of the memorysoftware code on the at least one device of the DSN includes:facilitating loading of the first version of the memory software code ona first device and a second device of the DSN, wherein a portion of thefirst test is performed on the first device and a differing portion ofthe first test is performed on the second device.
 14. The computingdevice of claim 11, wherein the first version of the memory softwarecode is in a middle of or approximately in the middle of the sequence ofinterim versions of the memory software code, and the second version ofthe memory software code is in a middle of or approximately in themiddle of the sub-sequence of the sequence of interim versions of thememory software code.
 15. The computing device of claim 11, whereinreceiving the indication of the software operational error resultingfrom testing performed on the current version of the memory softwarecode includes one or more selected from the group consisting of:interpreting an error message, selecting a test from a plurality ofsoftware tests, facilitating exercise of the memory software code inaccordance with a selected test, and indicating a software error when asoftware test resultant compares unfavorably to an expected softwaretest resultant.
 16. The computing device of claim 11, wherein receivingthe indication of the software operational error resulting from testingperformed on the current version of the memory software code includesone or more selected from the group consisting of: issuing, via theinterface, a test request to a storage unit of the DSN and receiving,via the interface, a test response from a storage unit of the DSN.
 17. Acomputer readable storage medium comprises: at least one memory sectionthat stores operational instructions that, when executed by one or moreprocessing modules of one or more computing devices of a dispersedstorage network (DSN), causes the one or more computing devices to:receive an indication of a software operational error resulting fromtesting performed on a current version of a memory software code; inresponse to receiving the indication of a software operational error,identify a sequence of interim versions of the memory software codebetween the current version of the memory software code and a previousversion of the memory software code associated with favorable softwareoperation; identify a first version of the memory software code from thesequence of interim versions of the memory software code; facilitate afirst test of the first version of the memory software code by at leastone device of the DSN; determine if the first test results in a testfailure; in response to determining that the first test does not resultin a test failure: identify a second version of the memory software codefrom the sequence of interim versions of the memory software code, wherethe second version of the memory software code is in a sub-sequence ofthe sequence of interim versions of the memory software code between thefirst version of the memory software code and the current version of thememory software code; and facilitate a second test, by the at least onedevice, of the second version of the memory software code; and inresponse to determining that the first test results in a test failure:identify a third version of the memory software code from the sequenceof interim versions of the memory software code, where the third versionof the memory software code is in a sub-sequence of the sequence ofinterim versions of the memory software code between the first versionof the memory software code and the previous version of the memorysoftware code associated with favorable software operation; andfacilitate a third test, by the at least one device, of the thirdversion of the memory software code.
 18. The computer readable storagemedium of claim 17, wherein the first version of the memory softwarecode is in a middle of or approximately in the middle of the sequence ofinterim versions of the memory software code, and the second version ofthe memory software code is in a middle of or approximately in themiddle of the sub-sequence of the sequence of interim versions of thememory software code.
 19. The computer readable storage medium of claim17, wherein receiving the indication of the software operational errorresulting from testing performed on the current version of the memorysoftware code includes one or more selected from the group consistingof: interpreting an error message, selecting a test from a plurality ofsoftware tests, facilitating exercise of the memory software code inaccordance with a selected test, and indicating a software error when asoftware test resultant compares unfavorably to an expected softwaretest resultant.
 20. The computing device of claim 11, wherein receivingthe indication of the software operational error resulting from testingperformed on the current version of the memory software code includesone or more selected from the group consisting of: issuing, via theinterface, a test request to a storage unit of the DSN and receiving,via the interface, a test response from a storage unit of the DSN.